Low-frequency Raman-active modes and temperature dependences in oligo-oxyethylene

1985 ◽  
Vol 23 (3) ◽  
pp. 471-481 ◽  
Author(s):  
K. Viras ◽  
T. A. King ◽  
C. Booth
Keyword(s):  
Low Frequency ◽  
Temperature Dependences

Low frequency ESR in the spin-glass :Mn: Lineshape and temperature dependences

1982 ◽  
Vol 43 (2) ◽  
pp. 109-112 ◽  
Author(s):  
F.R. Hoekstra ◽  
K. Baberschke ◽  
M. Zomack ◽  
J. Mydosh
Keyword(s):  
Spin Glass ◽  
Low Frequency ◽  
Temperature Dependences

Density and temperature effects on electron mobilities in gaseous, critical and liquid n-hexane, cyclohexane, and cyclopentane

1978 ◽  
Vol 56 (18) ◽  
pp. 2388-2395 ◽  
Author(s):  
Sam S. -S. Huang ◽  
Gordon R. Freeman
Keyword(s):  
Temperature Effects ◽  
Low Frequency ◽  
Inelastic Collisions ◽  
Negative Ion ◽  
Minimum Size ◽  
Molecular Cluster ◽  
Low Density ◽  
Temperature Coefficients ◽  
Temperature Dependences ◽  
Hydrocarbon Molecules

In the low density vapors the density normalized mobilities μn of thermal electrons decreased in the order n-hexane > cyclopentane > cyclohexane, although the differences were only ∼ 10%. The mobilities began to increase at electric field strengths E/n > 0.4 Td in cyclopentane, > 0.5 Td in cyclohexane and remained independent of field strength up to 1.5 Td in n-hexane. The ratio of the threshold drift velocity for electron heating to the speed of low frequency sound in the gas, υd(threshold)/c0 = 11 in cyclopentane, 14 in cyclohexane, and is > 35 in n-hexane; it increases with decreasing sphericity of the molecules. The electrons are cooled mainly by inelastic collisions with the hydrocarbon molecules. The temperature coefficients of mobilities in the low density gases increase as the molecules become more globular, which could reflect the participation of either low lying transient negative ion states or a Ramsauer–Townsend effect in the scattering processes. The normalized mobilities μn in the saturated vapors began to decrease at n = 4 × 1019 molecules/cm3 in n-hexane, 13 × 1019 in cyclohexane, and 30 × 1019 in cyclopentane. It appears that the minimum size of molecular cluster required for electron quasilocalization is smaller in n-hexane than in cyclohexane, and larger in cyclopentane. Electron localization interactions are weaker for more globular molecules.Mobilities in the critical fluids were 16 cm2/V s in n-hexane, 23 in cyclohexane, and 22 in cyclopentane.Mobilities in the liquids were independent of field up to the highest value used, which was 1.5 Td in the hexanes and 0.9 Td in cyclopentane. The mobilities and their temperature dependences were interpreted in terms of a model.

scholarly journals Влияние функционализации на электропроводность и шумовые характеристики массивов многостенных углеродных нанотрубок

2019 ◽  
Vol 89 (8) ◽  
pp. 1223
Author(s):  
В.А. Сергеев ◽  
Е.С. Климов ◽  
И.В. Фролов
Keyword(s):  
Acid Treatment ◽  
Low Frequency ◽  
Multiwall Carbon Nanotubes ◽  
Amplitude Distribution ◽  
Current Dependence ◽  
Noise Characteristics ◽  
Duration Distribution ◽  
Temperature Dependences ◽  
Multiwall Carbon ◽  
Semiconductor Type

AbstractThe electrophysical and noise characteristics of arrays of multiwall carbon nanotubes (MWCNTs) functionalized in various ways were studied. It is demonstrated that the as-prepared and annealed MWCNT arrays have semiconductor-type resistivities and temperature dependences of resistivity, while the arrays of annealed MWCNTs functionalized with acids have metallic properties. Low-frequency 1/ f noise in the 0.2‒20 kHz range was observed for all MWCNT arrays. Simple thermal annealing raised the noise level severalfold and annealing with acid treatment resulted in noise reduction and a change in the index of power in its current dependence. The normal amplitude distribution of noise spikes transformed to a lognormal one as the density of as-prepared MWCNT arrays increased. The duration distribution of these spikes became narrower at higher densities.

A Study on the Fine Structure of the Lateral Line Organ of the Sea Eel

1973 ◽  
Vol 31 ◽  
pp. 648-649
Author(s):  
K. Hama
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Lateral Line ◽  
Low Frequency ◽  
Sensory Cells ◽  
Apical Surface ◽  
Voltage Electron ◽  
Sensory Epithelia ◽  
Low Frequency Vibration ◽  
Transmission Electron

The lateral line organs of the sea eel consist of canal and pit organs which are different in function. The former is a low frequency vibration detector whereas the latter functions as an ion receptor as well as a mechano receptor.The fine structure of the sensory epithelia of both organs were studied by means of ordinary transmission electron microscope, high voltage electron microscope and of surface scanning electron microscope.The sensory cells of the canal organ are polarized in front-caudal direction and those of the pit organ are polarized in dorso-ventral direction. The sensory epithelia of both organs have thinner surface coats compared to the surrounding ordinary epithelial cells, which have very thick fuzzy coatings on the apical surface.

Lectin Binding to Human Breast Tumor Cells

1976 ◽  
Vol 34 ◽  
pp. 34-35
Author(s):  
Robert E. Nordquist ◽  
J. Hill Anglin ◽  
Michael P. Lerner
Keyword(s):  
Carcinoma Cell ◽  
Ricinus Communis ◽  
Lectin Binding ◽  
Low Frequency ◽  
Breast Carcinoma Cell Line ◽  
Human Breast ◽  
Human Breast Tumor ◽  
Duct Carcinoma ◽  
Specific Antigens ◽  
Ricin Agglutinin

A human breast carcinoma cell line (BOT-2) was derived from an infiltrating duct carcinoma (1). These cells were shown to have antigens that selectively bound antibodies from breast cancer patient sera (2). Furthermore, these tumor specific antigens could be removed from the living cells by low frequency sonication and have been partially characterized (3). These proteins have been shown to be around 100,000 MW and contain approximately 6% hexose and hexosamines. However, only the hexosamines appear to be available for lectin binding. This study was designed to use Concanavalin A (Con A) and Ricinus Communis (Ricin) agglutinin for the topagraphical localization of D-mannopyranosyl or glucopyranosyl and D-galactopyranosyl or DN- acetyl glactopyranosyl configurations on BOT-2 cell surfaces.

Practical High Resolution Microscopy

1968 ◽  
Vol 26 ◽  
pp. 302-303
Author(s):  
P. A. Marsh ◽  
T. Mullens ◽  
D. Price
Keyword(s):  
High Resolution ◽  
Magnetic Fields ◽  
Low Frequency ◽  
Resolving Power ◽  
Careful Attention ◽  
Electron Microscopes ◽  
The Relationship ◽  
High Resolution Microscopy ◽  
New Facilities

It is possible to exceed the guaranteed resolution on most electron microscopes by careful attention to microscope parameters essential for high resolution work. While our experience is related to a Philips EM-200, we hope that some of these comments will apply to all electron microscopes.The first considerations are vibration and magnetic fields. These are usually measured at the pre-installation survey and must be within specifications. It has been our experience, however, that these factors can be greatly influenced by the new facilities and therefore must be rechecked after the installation is completed. The relationship between the resolving power of an EM-200 and the maximum tolerable low frequency interference fields in milli-Oerstedt is 10 Å - 1.9, 8 Å - 1.4, 6 Å - 0.8.

Simulations of high-resolution images of amorphous silicon films

1986 ◽  
Vol 44 ◽  
pp. 544-545
Author(s):  
G. Y. Fan ◽  
J. M. Cowley
Keyword(s):  
Electron Microscope ◽  
High Frequency ◽  
Fourier Transformation ◽  
Amorphous Materials ◽  
Low Frequency ◽  
Chromatic Aberration ◽  
Structure Information ◽  
Frequency Components ◽  
High Resolution Images ◽  
Spatial Frequency Spectrum

It is well known that the structure information on the specimen is not always faithfully transferred through the electron microscope. Firstly, the spatial frequency spectrum is modulated by the transfer function (TF) at the focal plane. Secondly, the spectrum suffers high frequency cut-off by the aperture (or effectively damping terms such as chromatic aberration). While these do not have essential effect on imaging crystal periodicity as long as the low order Bragg spots are inside the aperture, although the contrast may be reversed, they may change the appearance of images of amorphous materials completely. Because the spectrum of amorphous materials is continuous, modulation of it emphasizes some components while weakening others. Especially the cut-off of high frequency components, which contribute to amorphous image just as strongly as low frequency components can have a fundamental effect. This can be illustrated through computer simulation. Imaging of a whitenoise object with an electron microscope without TF limitation gives Fig. 1a, which is obtained by Fourier transformation of a constant amplitude combined with random phases generated by computer.

SEM image sharpness analysis

1996 ◽  
Vol 54 ◽  
pp. 142-143
Author(s):  
M. T. Postek ◽  
A. E. Vladar
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Quantitative Information ◽  
Primary Electron ◽  
Image Sharpness ◽  
Critical Dimensions ◽  
Sem Image ◽  
Frequency Changes ◽  
Electron Microscopes ◽  
Scanning Electron

Fully automated or semi-automated scanning electron microscopes (SEM) are now commonly used in semiconductor production and other forms of manufacturing. The industry requires that an automated instrument must be routinely capable of 5 nm resolution (or better) at 1.0 kV accelerating voltage for the measurement of nominal 0.25-0.35 micrometer semiconductor critical dimensions. Testing and proving that the instrument is performing at this level on a day-by-day basis is an industry need and concern which has been the object of a study at NIST and the fundamentals and results are discussed in this paper.In scanning electron microscopy, two of the most important instrument parameters are the size and shape of the primary electron beam and any image taken in a scanning electron microscope is the result of the sample and electron probe interaction. The low frequency changes in the video signal, collected from the sample, contains information about the larger features and the high frequency changes carry information of finer details. The sharper the image, the larger the number of high frequency components making up that image. Fast Fourier Transform (FFT) analysis of an SEM image can be employed to provide qualitiative and ultimately quantitative information regarding the SEM image quality.

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